Field of Invention
The present invention relates to a method of processing a liquid sample containing an initial quantity of nucleic acids using a single-use, hereinafter disposable, plastic laboratory implement.
Description of Related Art
In particular disposable implements of this kind are reaction receptacles, pipet tips and also microtitration plates. In general the present invention applies to all plastic implements used in the laboratory that may be applicable in processing liquid samples containing nucleic acids.
Disposable laboratory implements of this kind are made of polypropylene. It has been widely observed that nucleic acids interact with conventional polypropylenes in a manner that under some conditions the nucleic acids will bond for instance to the walls of the reaction receptacles.
The interaction between nucleic acids and different polypropylene reaction receptacles is described for instance in CLINICAL NOTES of March 2001, pp 52. This article cites a fact also observed by the applicant that conventional polypropylenes will bond nucleic acids especially at high salt concentrations. The processing of nucleic acids entailing various steps in the phase transition range, that is at high salt concentrations, the possibility of impoverishing the nucleic acids of interest when using conventional polypropylene implements cannot be excluded.
The publication above mentions that all tested conventional propylene receptacles exhibit substantially the same adsorption properties as regards nucleic acids. A few receptacles made with special materials exhibited less bonding for nucleic acids; however the source of this feature could not be ascertained for lack of manufacturer data.
U.S. Pat. No. 6,544,417 discloses making illustratively polypropylene laboratory implements by adding additives to them in a manner that the biomolecule's bonding ability shall be reduced. The additives described in U.S. Pat. No. 6,544,417 always are other plastics, for instance fluoropolymers such as TEFLON. Rigorously speaking, the compositions described therein are not plastics containing additives but blends or compounds of two different plastics. Contrary to additive containing plastics, the mixtures of materials known from the above U.S. Patent do not permit making transparent laboratory implements.